package com.github.kezhenxu94.playground.leetcode;

/**
 * <pre>
 * 
 * 112. Path Sum
 * 
 * Given a binary tree and a sum, determine if the tree has a root-to-leaf path
 * such that adding up all the values along the path equals the given sum. For
 * example: Given the below binary tree and sum = 22,
 * 
 *             5
 *            / \
 *           4   8
 *          /   / \
 *         11  13  4
 *        /  \      \
 *       7    2      1
 * 
 * return true, as there exist a root-to-leaf path 5->4->11->2 which sum is 22.
 * 
 * </pre>
 * 
 * @author ke.zhen.xu
 *
 */
public class Solution112PathSum {

	public boolean hasPathSum(TreeNode root, int sum) {
		if (root == null)
			return false;
		if (sum == root.val && root.left == null && root.right == null)
			return true;
		return hasPathSum(root.left, sum - root.val) || hasPathSum(root.right, sum - root.val);
	}
}